High-Precision Distance Measurements with Classical Pulsating Stars
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Standing on the Shoulders of Giants: New Mass and Distance Estimates
Draft version October 15, 2020 Typeset using LATEX twocolumn style in AASTeX63 Standing on the shoulders of giants: New mass and distance estimates for Betelgeuse through combined evolutionary, asteroseismic, and hydrodynamical simulations with MESA Meridith Joyce,1, 2 Shing-Chi Leung,3 Laszl´ o´ Molnar,´ 4, 5, 6 Michael Ireland,1 Chiaki Kobayashi,7, 8, 2 and Ken'ichi Nomoto8 1Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611, Australia 2ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), Australia 3TAPIR, Walter Burke Institute for Theoretical Physics, Mailcode 350-17, Caltech, Pasadena, CA 91125, USA 4Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Konkoly-Thege ´ut15-17, H-1121 Budapest, Hungary 5MTA CSFK Lendulet¨ Near-Field Cosmology Research Group, Konkoly-Thege ´ut15-17, H-1121 Budapest, Hungary 6ELTE E¨otv¨os Lor´and University, Institute of Physics, Budapest, 1117, P´azm´any P´eter s´et´any 1/A 7Centre for Astrophysics Research, Department of Physics, Astronomy and Mathematics, University of Hertfordshire, College Lane, Hatfield AL10 9AB, UK 8Kavli Institute for the Physics and Mathematics of the Universe (WPI),The University of Tokyo Institutes for Advanced Study, The University of Tokyo, Kashiwa, Chiba 277-8583, Japan (Dated: Accepted XXX. Received YYY; in original form ZZZ) ABSTRACT We conduct a rigorous examination of the nearby red supergiant Betelgeuse by drawing on the synthesis of new observational data and three different modeling techniques. Our observational results include the release of new, processed photometric measurements collected with the space-based SMEI instrument prior to Betelgeuse's recent, unprecedented dimming event. -
Plotting Variable Stars on the H-R Diagram Activity
Pulsating Variable Stars and the Hertzsprung-Russell Diagram The Hertzsprung-Russell (H-R) Diagram: The H-R diagram is an important astronomical tool for understanding how stars evolve over time. Stellar evolution can not be studied by observing individual stars as most changes occur over millions and billions of years. Astrophysicists observe numerous stars at various stages in their evolutionary history to determine their changing properties and probable evolutionary tracks across the H-R diagram. The H-R diagram is a scatter graph of stars. When the absolute magnitude (MV) – intrinsic brightness – of stars is plotted against their surface temperature (stellar classification) the stars are not randomly distributed on the graph but are mostly restricted to a few well-defined regions. The stars within the same regions share a common set of characteristics. As the physical characteristics of a star change over its evolutionary history, its position on the H-R diagram The H-R Diagram changes also – so the H-R diagram can also be thought of as a graphical plot of stellar evolution. From the location of a star on the diagram, its luminosity, spectral type, color, temperature, mass, age, chemical composition and evolutionary history are known. Most stars are classified by surface temperature (spectral type) from hottest to coolest as follows: O B A F G K M. These categories are further subdivided into subclasses from hottest (0) to coolest (9). The hottest B stars are B0 and the coolest are B9, followed by spectral type A0. Each major spectral classification is characterized by its own unique spectra. -
The Interaction of Accretion Flux with Stellar Pulsation J.C
340 THE INTERACTION OF ACCRETION FLUX WITH STELLAR PULSATION J.C. Papaloizou J.E. Pringle The Institute of Astronomy, Cambridge, UK We consider the usual hypothesis that the short period coherent oscillations seen in cataclysmic variables are attributable to g-modes in a slowly rotating star, for details see Papaloizou and Pringle (1977). We show that this hypothesis is untenable for three main reasons: (i) the observed periods are too short for reasonable white dwarf models, (ii) the observed variability of the oscillations is too rapid and (iii) the expected rotation of the white dwarf, due to accretion, invalidates the slow rotation as sumption on which standard g-mode theory is based. We investigate the low frequency spectrum of a rotating pulsating star, taking the effects of rotation fully into account. In this case there are two sets of low frequency modes, the g-modes, and modes similar to Rossby waves in the Earth's atmosphere and oceans, which we designate r-modes. Typical periods for such modes are 1/m times the rotation period of the white dwarfs outer layers (m is the azimuthal wave number). We conclude that non-radial oscillations of white dwarfs can account for the properties of the oscillations seen in dwarf novae. References Papaloizou, J.C. and Pringle, J.E., 1977, Mon. Not R. Astr. Soc, in press. DISCUSSION of paper by PAPALOIZOU and PRINGLE: KIPPENHAHN: Since the vibrational stability of white dwarfs has been mentioned several times now, I would like to report on some unpublished results obtained by Lauterborn about 10 years ago. -
LIST of PUBLICATIONS Aryabhatta Research Institute of Observational Sciences ARIES (An Autonomous Scientific Research Institute
LIST OF PUBLICATIONS Aryabhatta Research Institute of Observational Sciences ARIES (An Autonomous Scientific Research Institute of Department of Science and Technology, Govt. of India) Manora Peak, Naini Tal - 263 129, India (1955−2020) ABBREVIATIONS AA: Astronomy and Astrophysics AASS: Astronomy and Astrophysics Supplement Series ACTA: Acta Astronomica AJ: Astronomical Journal ANG: Annals de Geophysique Ap. J.: Astrophysical Journal ASP: Astronomical Society of Pacific ASR: Advances in Space Research ASS: Astrophysics and Space Science AE: Atmospheric Environment ASL: Atmospheric Science Letters BA: Baltic Astronomy BAC: Bulletin Astronomical Institute of Czechoslovakia BASI: Bulletin of the Astronomical Society of India BIVS: Bulletin of the Indian Vacuum Society BNIS: Bulletin of National Institute of Sciences CJAA: Chinese Journal of Astronomy and Astrophysics CS: Current Science EPS: Earth Planets Space GRL : Geophysical Research Letters IAU: International Astronomical Union IBVS: Information Bulletin on Variable Stars IJHS: Indian Journal of History of Science IJPAP: Indian Journal of Pure and Applied Physics IJRSP: Indian Journal of Radio and Space Physics INSA: Indian National Science Academy JAA: Journal of Astrophysics and Astronomy JAMC: Journal of Applied Meterology and Climatology JATP: Journal of Atmospheric and Terrestrial Physics JBAA: Journal of British Astronomical Association JCAP: Journal of Cosmology and Astroparticle Physics JESS : Jr. of Earth System Science JGR : Journal of Geophysical Research JIGR: Journal of Indian -
Spectroscopy of Variable Stars
Spectroscopy of Variable Stars Steve B. Howell and Travis A. Rector The National Optical Astronomy Observatory 950 N. Cherry Ave. Tucson, AZ 85719 USA Introduction A Note from the Authors The goal of this project is to determine the physical characteristics of variable stars (e.g., temperature, radius and luminosity) by analyzing spectra and photometric observations that span several years. The project was originally developed as a The 2.1-meter telescope and research project for teachers participating in the NOAO TLRBSE program. Coudé Feed spectrograph at Kitt Peak National Observatory in Ari- Please note that it is assumed that the instructor and students are familiar with the zona. The 2.1-meter telescope is concepts of photometry and spectroscopy as it is used in astronomy, as well as inside the white dome. The Coudé stellar classification and stellar evolution. This document is an incomplete source Feed spectrograph is in the right of information on these topics, so further study is encouraged. In particular, the half of the building. It also uses “Stellar Spectroscopy” document will be useful for learning how to analyze the the white tower on the right. spectrum of a star. Prerequisites To be able to do this research project, students should have a basic understanding of the following concepts: • Spectroscopy and photometry in astronomy • Stellar evolution • Stellar classification • Inverse-square law and Stefan’s law The control room for the Coudé Description of the Data Feed spectrograph. The spec- trograph is operated by the two The spectra used in this project were obtained with the Coudé Feed telescopes computers on the left. -
Variable Star Classification and Light Curves Manual
Variable Star Classification and Light Curves An AAVSO course for the Carolyn Hurless Online Institute for Continuing Education in Astronomy (CHOICE) This is copyrighted material meant only for official enrollees in this online course. Do not share this document with others. Please do not quote from it without prior permission from the AAVSO. Table of Contents Course Description and Requirements for Completion Chapter One- 1. Introduction . What are variable stars? . The first known variable stars 2. Variable Star Names . Constellation names . Greek letters (Bayer letters) . GCVS naming scheme . Other naming conventions . Naming variable star types 3. The Main Types of variability Extrinsic . Eclipsing . Rotating . Microlensing Intrinsic . Pulsating . Eruptive . Cataclysmic . X-Ray 4. The Variability Tree Chapter Two- 1. Rotating Variables . The Sun . BY Dra stars . RS CVn stars . Rotating ellipsoidal variables 2. Eclipsing Variables . EA . EB . EW . EP . Roche Lobes 1 Chapter Three- 1. Pulsating Variables . Classical Cepheids . Type II Cepheids . RV Tau stars . Delta Sct stars . RR Lyr stars . Miras . Semi-regular stars 2. Eruptive Variables . Young Stellar Objects . T Tau stars . FUOrs . EXOrs . UXOrs . UV Cet stars . Gamma Cas stars . S Dor stars . R CrB stars Chapter Four- 1. Cataclysmic Variables . Dwarf Novae . Novae . Recurrent Novae . Magnetic CVs . Symbiotic Variables . Supernovae 2. Other Variables . Gamma-Ray Bursters . Active Galactic Nuclei 2 Course Description and Requirements for Completion This course is an overview of the types of variable stars most commonly observed by AAVSO observers. We discuss the physical processes behind what makes each type variable and how this is demonstrated in their light curves. Variable star names and nomenclature are placed in a historical context to aid in understanding today’s classification scheme. -
Commission G1 Binary and Multiple Star Systems 1
Transactions IAU, Volume XXXIA Reports on Astronomy 2018-2021 c 2021 International Astronomical Union Maria Teresa Lago, ed. DOI: 00.0000/X000000000000000X COMMISSION G1 BINARY AND MULTIPLE STAR SYSTEMS PRESIDENT Virginia Trimble VICE-PRESIDENT Christopher Adam Tout SECRETARY John Southworth ORGANIZING COMMITTEE Scott William Fleming, Ilya Mandel, Brian D. Mason, Terry D. Oswalt, Alexandre Roman-Lopes TRIENNIAL REPORT 2018{2021 1. Activities of IAU Commission G1 during 2018-2021 by Virginia Trimble (President), as transcribed by David Soderblom (Division G President) It has been a very good three years for binary and multiple systems of stars! If you go to the Astrophysics Data System (which we all know and use more often than we are perhaps prepared to admit) and ask it for any author in the period 2018-02 to 2021-02 and then, sequentially, \binary star," \double star," and \multiple system of stars" there comes back (or did on about 10 March 2020, for the three headings) 9,914 papers with 77,340 citations; 2,496 papers with 14,756 citations, and 3,982 papers with 24,069 citations, respectively. Thus if the three were human beings, they would have h indices of 88, 50, and 57 respectively. There is a small catch: the words do not have to be contiguous in the abstract or keywords, they just both have to be there, so a few of the papers retrieved are not even about astronomy. It is a bit like a very earnest, literal-minded dog, who, asked to bring The Times, returns with three discordant watches. The most-cited binary star paper was B.P. -
Determining Pulsation Period for an RR Lyrae Star
Leah Fabrizio Dr. Mitchell 06/10/2010 Determining Pulsation Period for an RR Lyrae Star As children we used to sing in wonderment of the twinkling stars above and many of us asked, “Why do stars twinkle?” All stars twinkle because their emitted light travels through the Earth’s atmosphere of turbulent gas and clouds that move and shift causing the traversing light to fluctuate. This means that the actual light output of the star is not changing. However there are a number of stars called Variable Stars that actually produce light of varying brightness before it hits the Earth’s atmosphere. There are two categories of variable stars: the intrinsic, where light fluctuation is due from the star physically changing and producing different luminosities, and extrinsic, where the amount of starlight varies due to another star eclipsing or blocking the star’s light from reaching earth (AAVSO 2010). Within the category of intrinsic variable stars are the pulsating variables that have a periodic change in brightness due to the actual size and light production of the star changing; within this group are the RR Lyrae stars (“variable star” 2010). For my research project, I will observe an RR Lyrae and find the period of its luminosity pulsation. The first RR Lyrae star was named after its namesake star (Strobel 2004). It was first found while astronomers were studying the longer period variable stars Cepheids and stood out because of its short period. In comparison to Cepheids, RR Lyraes are smaller and therefore fainter with a shorter period as well as being much older. -
Nd AAS Meeting Abstracts
nd AAS Meeting Abstracts 101 – Kavli Foundation Lectureship: The Outreach Kepler Mission: Exoplanets and Astrophysics Search for Habitable Worlds 200 – SPD Harvey Prize Lecture: Modeling 301 – Bridging Laboratory and Astrophysics: 102 – Bridging Laboratory and Astrophysics: Solar Eruptions: Where Do We Stand? Planetary Atoms 201 – Astronomy Education & Public 302 – Extrasolar Planets & Tools 103 – Cosmology and Associated Topics Outreach 303 – Outer Limits of the Milky Way III: 104 – University of Arizona Astronomy Club 202 – Bridging Laboratory and Astrophysics: Mapping Galactic Structure in Stars and Dust 105 – WIYN Observatory - Building on the Dust and Ices 304 – Stars, Cool Dwarfs, and Brown Dwarfs Past, Looking to the Future: Groundbreaking 203 – Outer Limits of the Milky Way I: 305 – Recent Advances in Our Understanding Science and Education Overview and Theories of Galactic Structure of Star Formation 106 – SPD Hale Prize Lecture: Twisting and 204 – WIYN Observatory - Building on the 308 – Bridging Laboratory and Astrophysics: Writhing with George Ellery Hale Past, Looking to the Future: Partnerships Nuclear 108 – Astronomy Education: Where Are We 205 – The Atacama Large 309 – Galaxies and AGN II Now and Where Are We Going? Millimeter/submillimeter Array: A New 310 – Young Stellar Objects, Star Formation 109 – Bridging Laboratory and Astrophysics: Window on the Universe and Star Clusters Molecules 208 – Galaxies and AGN I 311 – Curiosity on Mars: The Latest Results 110 – Interstellar Medium, Dust, Etc. 209 – Supernovae and Neutron -
Gaia Data Release 2 Special Issue
A&A 623, A110 (2019) Astronomy https://doi.org/10.1051/0004-6361/201833304 & © ESO 2019 Astrophysics Gaia Data Release 2 Special issue Gaia Data Release 2 Variable stars in the colour-absolute magnitude diagram?,?? Gaia Collaboration, L. Eyer1, L. Rimoldini2, M. Audard1, R. I. Anderson3,1, K. Nienartowicz2, F. Glass1, O. Marchal4, M. Grenon1, N. Mowlavi1, B. Holl1, G. Clementini5, C. Aerts6,7, T. Mazeh8, D. W. Evans9, L. Szabados10, A. G. A. Brown11, A. Vallenari12, T. Prusti13, J. H. J. de Bruijne13, C. Babusiaux4,14, C. A. L. Bailer-Jones15, M. Biermann16, F. Jansen17, C. Jordi18, S. A. Klioner19, U. Lammers20, L. Lindegren21, X. Luri18, F. Mignard22, C. Panem23, D. Pourbaix24,25, S. Randich26, P. Sartoretti4, H. I. Siddiqui27, C. Soubiran28, F. van Leeuwen9, N. A. Walton9, F. Arenou4, U. Bastian16, M. Cropper29, R. Drimmel30, D. Katz4, M. G. Lattanzi30, J. Bakker20, C. Cacciari5, J. Castañeda18, L. Chaoul23, N. Cheek31, F. De Angeli9, C. Fabricius18, R. Guerra20, E. Masana18, R. Messineo32, P. Panuzzo4, J. Portell18, M. Riello9, G. M. Seabroke29, P. Tanga22, F. Thévenin22, G. Gracia-Abril33,16, G. Comoretto27, M. Garcia-Reinaldos20, D. Teyssier27, M. Altmann16,34, R. Andrae15, I. Bellas-Velidis35, K. Benson29, J. Berthier36, R. Blomme37, P. Burgess9, G. Busso9, B. Carry22,36, A. Cellino30, M. Clotet18, O. Creevey22, M. Davidson38, J. De Ridder6, L. Delchambre39, A. Dell’Oro26, C. Ducourant28, J. Fernández-Hernández40, M. Fouesneau15, Y. Frémat37, L. Galluccio22, M. García-Torres41, J. González-Núñez31,42, J. J. González-Vidal18, E. Gosset39,25, L. P. Guy2,43, J.-L. Halbwachs44, N. C. Hambly38, D. -
Cepheid Variable Stars Cepheid Variable Stars As Distance Indicators
Cepheid Variable Stars Cepheid variable stars as distance indicators. Certain stars that have used up their main supply of hydrogen fuel are unstable and pulsate. RR Lyrae variables have periods of about a day. Their brightness doubles from dimest to brightest. Typical light curve for a Cepheid variable star. Cepheid variables have longer periods, from one day up to about 50 days. Their brightness also doubles from dimest to brightest. From the shape of the ``light curve'' of a Cepheid variable star, one can tell that it is a Cepheid variable. The period is simple to measure, as is the apparent brightness at maximum brightness. Cepheids as distance indicators Cepheids are important beyond their intrinsic interest as pulsating stars. Astronomomers have found that their is a relation between the period of a Cepheid and its luminosity. http://zebu.uoregon.edu/~soper/MilkyWay/cepheid.html (1 of 3) [5/25/1999 10:34:08 AM] Cepheid Variable Stars This enables astronomers to determine distances: ● Find the period. ● This gives the luminosity. ● Measure the apparent brightness. ● Determine the distance from the luminosity and brightness. The same applies to RR Lyrae variable stars. Once you know that a star is an RR Lyrae variable (eg. from the shape of its light curve), then you know its luminosity. Where did this period-luminosity relation come from? ● American astronomer Henrietta Leavitt looked at many Cepheid variables in the Small Magellanic Cloud (a satellite galaxy to ours.) ● She found the period luminosity relation (reported in 1912). ● One needs a distance measurement from some other method for at least one Cepheid. -
A Comprehensive Study of Cepheid Variables in the Andromeda Galaxy Period Distribution, Blending, and Distance Determination
A&A 473, 847–855 (2007) Astronomy DOI: 10.1051/0004-6361:20077960 & c ESO 2007 Astrophysics A comprehensive study of Cepheid variables in the Andromeda galaxy Period distribution, blending, and distance determination F. Vilardell1,C.Jordi1,3, and I. Ribas2,3 1 Departament d’Astronomia i Meteorologia, Universitat de Barcelona, c/ Martí i Franquès, 1, 08028 Barcelona, Spain e-mail: [francesc.vilardell;carme.jordi]@am.ub.es 2 Institut de Ciències de l’Espai-CSIC, Campus UAB, Facultat de Ciències, Torre C5-parell-2a, 08193 Bellaterra, Spain e-mail: [email protected] 3 Institut d’Estudis Espacials de Catalunya (IEEC), Edif. Nexus, c/ Gran Capità, 2-4, 08034 Barcelona, Spain Received 28 May 2007 / Accepted 18 July 2007 ABSTRACT Extragalactic Cepheids are the basic rungs of the cosmic distance scale. They are excellent standard candles, although their lumi- nosities and corresponding distance estimates can be affected by the particular properties of the host galaxy. Therefore, the accurate analysis of the Cepheid population in other galaxies, and notably in the Andromeda galaxy (M 31), is crucial to obtaining reliable distance determinations. We obtained accurate photometry (in B and V passbands) of 416 Cepheids in M 31 over a five year campaign within a survey aimed at the detection of eclipsing binaries. The resulting Cepheid sample is the most complete in M 31 and has almost the same period distribution as the David Dunlap Observatory sample in the Milky Way. The large number of epochs (∼250 per filter) has permitted the characterisation of the pulsation modes of 356 Cepheids, with 281 of them pulsating in the fundamental mode and 75 in the first overtone.